1. Field of the Invention
The present invention relates to a ratcheting mechanism for enabling rotation of sockets, screw driver blades, and other objects. The wrench comprises a handle giving the user leverage, and a working head which is either directly usable with square or otherwise configured drives, screw driving blades, and the like, or which may have a receptacle for interchangeably accepting various tool driving shafts.
2. Description of the Prior Art
Reversible ratcheting tools have long been desired by service and assembly mechanics and technicians for installing and removing threaded fasteners. For the convenience of the technician, it is important that a tool be quickly converted to include any desired driver, blade, socket, and so forth, since efficiency of assembly and disassembly is usually directly linked to the technician's compensation. For this reason, reversible wrenches have become quite popular.
A second desirable aspect is that a single driving tool accept interchangeable drivers, blades, sockets, fasteners, and like accessories cooperating with the driver. These drivers, blades, sockets, and like accessories will be referred to hereinafter as tools. Interchangeability enables a single wrench to perform many tasks. The wrench can gain added capabilities as additional tools are made available. This arrangement has favorable economic repercussions, since each additional size or configuration requires a working element or tool of limited complexity and cost.
An additional desirable aspect is that the wrench have as few separate parts as possible. In traditional reversible ratcheting wrench driving tools, separate internal and external parts are required to adjust the direction of operation. However, it is possible to design the wrench so as to eliminate such intermediate components. An example is seen in U.S. Pat. No. 161,022, issued to George W. Freeman on Mar. 23, 1875. The Freeman wrench has a rotatable inner member occupying a generally round cavity formed in the head thereof. The inner member has external teeth which engage a single internal tooth formed in the cavity of the head of the wrench. Both internal and external teeth have one side oriented at a severe angle to a line tangential with the respective rounded shape of the inner member or of the round cavity of the head of the wrench, the other side oriented at a slight angle to the tangential line. This arrangement is typical of pawl and ratchet devices.
However, the internal geometry and structure of this wrench differ from those of the present invention, and the differences, although some aspects being so slight as not to be readily discernible upon casual inspection, lead to significantly different performance characteristics.
Careful examination of the Freeman wrench will reveal that the internal rotatable member is not surroundably constrained in the manner of the present invention. It is possible that the rotatable member in Freeman's device will rotate out of an engaged position with respect to the fixed encircling member of the tool after only a very limited degree of rotation in response to resistance to torque applied to the wrench. In the present invention, the encircling member is dimensioned and configured to avoid this occurrence.
A number of other prior art wrenches providing reversibility and plural driving features will be reviewed. A wrench having a removable socket is shown in U.S. Pat. No. 4,276,791, issued to John W. Thompson on Jul. 7, 1981. The wrench includes the usual bipositionable pawl, and has a lever and linkage for adjusting the driving direction. The present invention is unencumbered by such a pawl and linkage.
U.S. Pat. No. 4,807,500, issued to Harvey M. Main, on Feb. 28, 1989, illustrates a ratcheting tool wherein a circular internal member has teeth disposed along only a portion of its circumference. In the present invention, it is the surrounding member that has teeth disposed on the generally circular surface of the cavity formed therein, these teeth being arranged in two diametrically opposed groups. Also, the complex, multi-part construction of the internal member of Main is replaced by a single part corresponding member in the present invention. Configuration of the cavity of the present invention is carefully varied from circular to achieve new results not seen in Main.
U.S. Pat. No. 1,359,325, issued to William A. Butler on Nov. 16, 1920, describes a ratchet wrench having a driven member disposed in an elongated slot, the driven member being able to move in the slot. Butler lacks cavity geometry and an arrangement of driving teeth disposed in two diametrically opposed groups on the internal surface of the cavity, both of these features being found in the present invention.
Italian Patent No. 603807, issued to Orlando Contini on Apr. 13, 1960, shows a ratcheting tool having tooth contact occurring along a limited length of the circumference of the circular driven member. However, the subject tool is not surrounded and constrained in the manner of the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.